First let's establish that bsky.app is not decentralized. They hold your keys and your data. If they disagree (morally or legally) with what you say, you have no recourse. Since they hold your keys, they can rewrite your history however they wish and it will be authoritative.

Your argument is really that ATproto is decentralized. First, I would argue that it's federated, as users have a "home" PDS. This is different than nostr, where you can spray events across every relay, or store them in a file, or send them to a friend over BLE, and they are *equally authoritative*.

Second, these ATproto apps aren't actually using ATproto: they're connecting to a Bluesky API. Perhaps they use a serialization format from ATproto, but they're simply asking nicely for AppView to take actions.

Third, it doesn't matter what ATproto is capable of, as people are there for bsky.app. Important features like account management, message deletion, and content filtering are done inside bsky and not using ATproto.

So, as fiatjaf points out, when bsky decides that doing everything in a truly decentralized manner is too difficult and sunsets ATproto, no one using the service will even be bothered.

Just like XMPP